mlx4/en_netdev: allow offloading VXLAN over VLAN

ConnectX-3 Pro can offload transmission of VLAN packets with VXLAN inside:
enable tunnel offloads in dev->vlan_features, like it's done with other
NIC drivers (e.g. be2net and ixgbe).

It's no more necessary to change dev->hw_enc_features when VXLAN are added
or removed, since .ndo_features_check() already checks for VXLAN packet
where the UDP destination port matches the configured value. Just set
dev->hw_enc_features when the NIC is initialized, so that overlying VLAN
can correctly inherit the tunnel offload capabilities.

Changes since v1:
- avoid flipping hw_enc_features, instead of calling netdev notifiers,
thanks to Saeed Mahameed
- squash two patches into a single one

CC: Paolo Abeni <[e-mail]>
CC: Marcelo Ricardo Leitner <[e-mail]>
Signed-off-by: Davide Caratti <[e-mail]>
Reviewed-by: Saeed Mahameed <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/ethernet/mellanox/mlx4/en_netdev.c

···
 		en_err(priv, "failed setting L2 tunnel configuration ret %d\n", ret);
 		return;
 	}
-
-	/* set offloads */
-	priv->dev->hw_enc_features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
-				      NETIF_F_RXCSUM |
-				      NETIF_F_TSO | NETIF_F_TSO6 |
-				      NETIF_F_GSO_UDP_TUNNEL |
-				      NETIF_F_GSO_UDP_TUNNEL_CSUM |
-				      NETIF_F_GSO_PARTIAL;
 }
 
 static void mlx4_en_del_vxlan_offloads(struct work_struct *work)
···
 	int ret;
 	struct mlx4_en_priv *priv = container_of(work, struct mlx4_en_priv,
 						 vxlan_del_task);
-	/* unset offloads */
-	priv->dev->hw_enc_features &= ~(NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
-					NETIF_F_RXCSUM |
-					NETIF_F_TSO | NETIF_F_TSO6 |
-					NETIF_F_GSO_UDP_TUNNEL |
-					NETIF_F_GSO_UDP_TUNNEL_CSUM |
-					NETIF_F_GSO_PARTIAL);
-
 	ret = mlx4_SET_PORT_VXLAN(priv->mdev->dev, priv->port,
 				  VXLAN_STEER_BY_OUTER_MAC, 0);
 	if (ret)
···
 	if (mdev->LSO_support)
 		dev->hw_features |= NETIF_F_TSO | NETIF_F_TSO6;
 
+	if (mdev->dev->caps.tunnel_offload_mode ==
+	    MLX4_TUNNEL_OFFLOAD_MODE_VXLAN) {
+		dev->hw_features |= NETIF_F_GSO_UDP_TUNNEL |
+				    NETIF_F_GSO_UDP_TUNNEL_CSUM |
+				    NETIF_F_GSO_PARTIAL;
+		dev->features    |= NETIF_F_GSO_UDP_TUNNEL |
+				    NETIF_F_GSO_UDP_TUNNEL_CSUM |
+				    NETIF_F_GSO_PARTIAL;
+		dev->gso_partial_features = NETIF_F_GSO_UDP_TUNNEL_CSUM;
+		dev->hw_enc_features = NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
+				       NETIF_F_RXCSUM |
+				       NETIF_F_TSO | NETIF_F_TSO6 |
+				       NETIF_F_GSO_UDP_TUNNEL |
+				       NETIF_F_GSO_UDP_TUNNEL_CSUM |
+				       NETIF_F_GSO_PARTIAL;
+	}
+
 	dev->vlan_features = dev->hw_features;
 
 	dev->hw_features |= NETIF_F_RXCSUM | NETIF_F_RXHASH;
···
 		en_warn(priv,
 			"No RSS hash capabilities exposed, using Toeplitz\n");
 		priv->rss_hash_fn = ETH_RSS_HASH_TOP;
-	}
-
-	if (mdev->dev->caps.tunnel_offload_mode == MLX4_TUNNEL_OFFLOAD_MODE_VXLAN) {
-		dev->hw_features |= NETIF_F_GSO_UDP_TUNNEL |
-				    NETIF_F_GSO_UDP_TUNNEL_CSUM |
-				    NETIF_F_GSO_PARTIAL;
-		dev->features    |= NETIF_F_GSO_UDP_TUNNEL |
-				    NETIF_F_GSO_UDP_TUNNEL_CSUM |
-				    NETIF_F_GSO_PARTIAL;
-		dev->gso_partial_features = NETIF_F_GSO_UDP_TUNNEL_CSUM;
 	}
 
 	/* MTU range: 68 - hw-specific max */